Method for blocking outflow of petroleum or the like due to damage to subsea petroleum well steel pipe or the like

ABSTRACT

The present invention relates to blocking a flow of crude oil or natural gas from a steel pipe for extracting the oil or the like that has been installed in the sea when the steel pipe is broken. When a steel pipe  4  for petroleum well in the deep sea is broken, a carrying pipe  6  is inserted from a hole  5  that is a broken point in the steel pipe  4  to a predetermined depth and is fixed. The carrying pipe  6  is an elongated pipe made of nonmagnetic material such as synthetic resin. The carrying pipe  6  has a diameter that is approximately one-half the diameter of the steel pipe  4 . A circular mesh plate  8  is hung at a tip portion of the carrying pipe  6.  After that, magnetic particles  20  or the like having a diameter of several to several tens of millimeters are dropped from an upper opening  7  of the carrying pipe  6  in a randomly dispersed manner so as to cause the magnetic particles  20  or the like to magnetically adhere to the inner surface of the steel pipe  4  near the circular mesh plate  8  provided at the tip portion of the carrying pipe  6  and adhere to each other to form a mass. The outflow of crude oil is thereby suppressed. After that, concrete  24  is injected from the upper opening  7  of the carrying pipe  6  and cured, as a result of which the outflow of petroleum or the like is blocked.

TECHNICAL FIELD

The present invention blocks a flow of crude oil or natural gas from a steel pipe for extracting the oil or the like that has been installed in the sea when the steel pipe is broken.

BACKGROUND ART

As a method to, when oil flows out from a hole caused by damage to a subsea petroleum well steel pipe, block the hole, inserting a carrying pipe from the hole and injecting concrete is conceivable. However, even if this method is carried out, it is not possible to cure concrete because the outflow pressure of oil pushes back the concrete and the concrete is dispersed in the seawater.

Accordingly, the following method may be used as an alternative. A steel pipe is buried near the place where a petroleum well steel pipe has been buried in the seafloor. Then, the steel pipe is connected to the side wall of the damaged steel pipe in the place where it has been buried in the seafloor. Then, a barrier material is charged through the steel pipe so as to suppress the outflow of oil. After that, concrete is injected. This method, however, requires troublesome large-scale work, and it is therefore difficult to complete in a short time.

SUMMARY OF INVENTION Technical Problem

Mere insertion of a carrying pipe into a hole caused by damage to a subsea petroleum well steel pipe results in, even if concrete is injected, the concrete being pushed back by the outflow pressure of oil. Accordingly, an object of the present invention is to provide a method with which the outflow of crude oil is suppressed prior to injection of concrete.

Method of Solving the Problem

When a steel pipe 4 for petroleum or natural gas well that has been installed in the sea is broken, a carrying pipe 6 is inserted from a hole 5 that is a broken point in the steel pipe 4 to a predetermined depth and is fixed. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin. The carrying pipe 6 has a diameter that is approximately one-half the diameter of the steel pipe 4. A circular mesh plate 8 is hung at a tip portion of the carrying pipe 6. After that, magnetic particles 20 or the like having a diameter of several to several tens of millimeters are dropped from an upper opening 7 of the carrying pipe 6 in a randomly dispersed manner so as to cause the magnetic particles 20 or the like to magnetically adhere to the inner surface of the steel pipe 4 near the circular mesh plate 8 provided at the tip portion of the carrying pipe 6 and adhere to each other to form a mass. The outflow of crude oil is thereby suppressed. After that, concrete 24 is injected from the upper opening 7 of the carrying pipe 6 and cured, as a result of which the outflow of petroleum or the like is blocked.

The carrying pipe 6 may be suspended in advance inside the steel pipe 4 for petroleum or natural gas well that has been installed in the sea, so as to reach a position deeper than near the seafloor where the steel pipe 4 is likely to break. The circular mesh plate 8 is hung at the tip portion of the carrying pipe 6. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin. If the steel pipe 4 is cracked or damaged, then immediately, magnetic particles 20 or the like having a diameter of several to several tens of millimeters are dropped from the upper opening 7 of the carrying pipe 6 in a dispersed manner so as to cause the magnetic particles 20 or the like to magnetically adhere to the inner surface of the steel pipe 4 near the circular mesh plate 8 provided at the tip portion of the carrying pipe 6 and adhere to each other to form a mass. The outflow of petroleum or natural gas is thereby suppressed. After that, concrete 24 or the like is injected from the upper opening 7 of the carrying pipe 6 and cured, as a result of which the outflow of petroleum or the like is blocked.

When dropping the magnetic particles 20 or the like in the elongated carrying pipe 6 made of nonmagnetic material such as synthetic resin and suspended inside the steel pipe 4 for petroleum or natural gas well that has been installed in the sea, the upper opening 7 of the carrying pipe 6 is hermetically sealed with an feeding equipment 12 for feeding magnetic particles or the like so as to suppress an internal flow in the carrying pipe 6. After the internal flow in the carrying pipe 6 has been suppressed, the magnetic particles 20 or the like loaded into a feeding opening 15 is dropped in the carrying pipe 6, whereby the magnetic particles 20 or the like fall to a lower end of the carrying pipe 6 without resistance, move along the flow of petroleum or the like in the steel pipe 4, reach a conical metal mesh 11 attached to the carrying pipe 6, are blocked up by the conical metal mesh 11 and magnetically adhere to the inner surface of the steel pipe 4. A resulting adherent layer gradually grows downward so that the magnetic particles 20 or the like reach the circular mesh plate 8 provided at the tip portion of the carrying pipe 6, fill inside of the steel pipe 4 and form a mass due to magnetic force, suppressing the outflow of petroleum or natural gas. After the outflow of petroleum or natural gas has been suppressed, a ball valve 19 or the like provided at an upper portion of the carrying pipe 6 is opened and the concrete 24 or the like is injected and cured, as a result of which the outflow of petroleum or natural gas is blocked.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view showing a method for blocking a flow of oil from a hole caused by damage to a subsea petroleum well pipe according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view showing a part of FIG. 1.

FIG. 3 is a cross-sectional view taken along the line A-A shown in FIG. 2.

FIG. 4 is a vertical cross-sectional view showing a state in which a steel pipe including a carrying pipe therein according to an embodiment of the present invention has been cracked.

FIG. 5 is an enlarged vertical cross-sectional view showing a part of FIG. 4.

FIG. 6 is a cross-sectional view taken along the line B-B shown in FIG. 5.

FIG. 7 is a vertical cross-sectional view showing the initial stage of charging magnetic particles into a steel pipe according to an embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view showing the final stage of charging magnetic particles into the steel pipe.

FIG. 9 is a vertical cross-sectional view showing a state in which a feeding equipment for feeding magnetic particles or the like has been attached above a carrying pipe of the present invention.

FIG. 10 is a cross-sectional view taken along the line C-C shown in FIG. 9.

FIG. 11 is a vertical cross-sectional view of a steel wire rope-reinforced polyethylene carrying pipe used to carry out the present invention.

FIG. 12 is a cross-sectional view taken along the line D-D shown in FIG. 11.

DESCRIPTION OF EMBODIMENTS

When a steel pipe 4 for petroleum or natural gas well that has been installed in the sea is broken, a carrying pipe 6 is inserted from a hole 5 that is a broken point in the steel pipe 4 to a predetermined depth and is fixed. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin. The carrying pipe 6 has a diameter that is approximately one-half the diameter of the steel pipe 4. A circular mesh plate 8 is hung at a tip portion of the carrying pipe 6. After that, magnetic particles 20 or the like having a diameter of several to several tens of millimeters are dropped from an upper opening 7 of the carrying pipe 6 in a randomly dispersed manner so as to cause the magnetic particles 20 or the like to magnetically adhere to the inner surface of the steel pipe 4 near the circular mesh plate 8 provided at the tip portion of the carrying pipe 6 and adhere to each other to form a mass. The outflow of crude oil is thereby suppressed. After that, concrete 24 is injected from the upper opening 7 of the carrying pipe 6 and cured, as a result of which the outflow of petroleum or the like is blocked.

The carrying pipe 6 may be suspended in advance inside the steel pipe 4 for petroleum or natural gas well that has been installed in the sea, so as to reach a position deeper than near the seafloor where the steel pipe 4 is likely to break. The circular mesh plate 8 is hung at the tip portion of the carrying pipe 6. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin. If the steel pipe 4 is cracked or damaged, then immediately, magnetic particles 20 or the like having a diameter of several to several tens of millimeters are dropped from the upper opening 7 of the carrying pipe 6 in a dispersed manner so as to cause the magnetic particles 20 or the like to magnetically adhere to the inner surface of the steel pipe 4 near the circular mesh plate 8 provided at the tip portion of the carrying pipe 6 and adhere to each other to form a mass. The outflow of petroleum or natural gas is thereby suppressed. After that, concrete 24 or the like is injected from the upper opening 7 of the carrying pipe 6 and cured, as a result of which the outflow of petroleum or the like is blocked.

As the carrying pipe 6, pipes made of nonmagnetic material can be used such as a polyethylene pipe, a steel wire rope-reinforced polyethylene pipe, an impact resistant vinyl chloride pipe and a stainless steel pipe. It is most appropriate to use a steel wire rope-reinforced polyethylene pipe 26 as the carrying pipe 6. As used herein, “steel wire rope-reinforced polyethylene pipe 26” refers to a pipe reinforced with a plurality of flexible steel wire ropes 19 in order to resist breakage of the steel pipe 4. The plurality of flexible steel wire ropes 19 are circumferentially disposed and buried inside the pipe wall and each extends in the axial direction thereof. There are projections and depressions in the surface of a steel wire rope 19, and thus the steel wire rope 19 can be firmly adhered to and integrated with polyethylene resin. A pipe connector 28 for connecting the pipes includes a reinforcing metal mesh 29 buried near the outer circumference surface and a nichrome wire 30 buried near the inner circumference surface. The pipe connector 28 is produced by injection molding. An end of the steel wire rope-reinforced polyethylene pipe 26 is inserted into a receptacle in the inner circumference of the pipe connector 28, and electric current is applied to nichrome wire terminals 31 so as to fuse the steel wire rope-reinforced polyethylene pipe 26 and the pipe connector 28. The fusion can provide sufficient resistance to external tensile force.

The magnetic particles 20 have a size ranging from several to several tens of millimeters. The magnetic particles 20 may be mixed with sand or the like, and loaded into a feeding opening 15 and rotationally dropped. The shape of the magnetic particles 20 can be spherical, circular platform-shaped, tombstone-shaped, cube-shaped, droplet-shaped, round bar-shaped, rectangular bar-shaped or the like. The magnetic particles 20 may be mixed with steel balls, iron sand or the like and used.

In the case where a plurality of magnetic particles 20 are simultaneously dropped, a method is used in which the particles are separately wrapped in clay or mixed with a large amount of sand, and then dropped at once by using an equipment for hermetically sealing and dropping large magnetic particles or the like.

As shown in FIG. 4, inside the steel pipe 4 for petroleum or natural gas well that has been installed in the sea, the carrying pipe 6 is lowered in advance into the seafloor, which is deeper than near the seafloor where the steel pipe 4 is likely to break. The circular mesh plate 8 is attached to the tip portion of the carrying pipe 6 and a conical metal mesh 11 is mounted inside the carrying pipe 6. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin.

The circular mesh plate 8 has a structure in which it is suspended by a hanger bar 9 made of copper alloy or stainless steel. The conical metal mesh 11 is made of copper alloy or stainless steel. The conical metal mesh 11 is sized such that its outer circumference is contact with the inner circumference of the steel pipe 4. Instead of the conical metal mesh 11, a tea whisk-shaped metal obtained by finely splitting and flaring the top half of a thin-wall cylinder may be used.

An outer circumference 16 and two side faces 17 of a rotating disc 14 of the feeding equipment 12 for feeding magnetic particles or the like are provided so as to be slidably rotate without creating a gap with a main body 18 of the feeding equipment 12 for feeding magnetic particles or the like. Accordingly, the petroleum or the like contained in the carrying pipe 6 can be completely hermetically sealed. Consequently, it is possible to completely prevent the petroleum or the like from flowing upward.

When the magnetic particles 20 or the like are loaded into feeding openings 15 of the rotating disc 14 and the rotating disc 14 is rotated to sequentially drop the magnetic particles 20, the magnetic particles 20 or the like fall to a lower end of the carrying pipe 6 without resistance. This is because the flow of petroleum or the like in the carrying pipe 6 has been suppressed. The magnetic particles 20 or the like are swept along the flow of petroleum or the like in the steel pipe 4 in the direction indicated by arrow A shown in FIG. 7 and reach the conical metal mesh 11 attached to the carrying pipe 6. The magnetic particles 20 or the like are blocked up by the conical metal mesh 11 and magnetically adhere to the inner surface of the steel pipe 4. The resulting adherent layer gradually grows downward and reaches the circular mesh plate 8 provided at the tip portion of the carrying pipe 6. The magnetic particles 20 or the like then fill the inside of the steel pipe 4 and form a mass due to magnetic force, suppressing the outflow of petroleum or natural gas. After that, a ball valve 19 or the like provided at an upper portion of the carrying pipe 6 is opened, and concrete 24 or the like is injected and cured, whereby the outflow of petroleum or natural gas can be blocked.

When damage does not occur to the steel pipe 4, petroleum or the like can be extracted from the ball valve 19 provided at the upper portion of the carrying pipe 6.

INDUSTRIAL APPLICABILITY

This method that uses magnetic particles can be widely used in the event of an emergency such as the pipe being damaged.

REFERENCE SIGNS LIST

-   -   1 Sea Surface     -   2 Seafloor     -   3 Seawater     -   4 Petroleum Well Steel Pipe     -   5 Broken Point in Petroleum Well Steel Pipe     -   6 Carrying Pipe     -   7 Upper Opening of Carrying Pipe     -   8 Circular Mesh Plate     -   9 Hanger Bar of Circular Mesh Plate     -   10 Fixing Bolt of Hanger Bar     -   11 Conical Metal Mesh     -   12 Feeding Equipment for Feeding Magnetic Particles or the Like     -   13 Main Body     -   14 Rotating Disc     -   15 Feeding Opening of Rotating Disc     -   16 Outer Circumference of Rotating Disc     -   17 Side Face of Rotating Disc     -   18 Motor for Driving Rotating Disc     -   19 Ball Valve     -   20 Magnetic Particles     -   21 Magnetic Particles Mixed with Sand     -   22 Pebbles     -   23 Steel Balls     -   24 Concrete     -   25 Base     -   26 Steel Wire Rope-Reinforced Polyethylene Pipe     -   27 Steel Wire Rope     -   28 Reinforced Polyethylene Pipe Connector     -   29 Reinforcing Metal Mesh     -   30 Nichrome Wire     -   31 Nichrome Wire Terminal 

1. A method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like, the method comprising: when a steel pipe for petroleum or natural gas well that has been installed in the sea is broken, inserting an elongated carrying pipe made of nonmagnetic material such as synthetic resin from a hole that is a broken point in the steel pipe to a predetermined depth and fixing the carrying pipe, the carrying pipe having a diameter that is approximately one-half a diameter of the steel pipe, and a circular mesh plate 8 being provided at a tip portion of the carrying pipe; after the carrying pipe has been fixed, dropping magnetic particles or the like having a diameter of several to several tens of millimeters from an upper opening of the carrying pipe in a randomly dispersed manner so as to cause the magnetic particles or the like to magnetically adhere to an inner surface of the steel pipe near the circular mesh plate provided at the tip portion of the carrying pipe and adhere to each other to form a mass, thereby suppressing the outflow of crude oil; and after the outflow of crude oil has been suppressed, injecting concrete from the upper opening of the carrying pipe and curing the concrete.
 2. The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to claim 1, comprising: suspending in advance, inside the steel pipe for petroleum or natural gas well that has been installed in the sea, the elongated carrying pipe made of nonmagnetic material such as synthetic resin, so as to reach a position deeper than near the seafloor where the steel pipe is likely to break, the circular mesh plate being provided at the tip portion of the carrying pipe; when the steel pipe is cracked or damaged, dropping the magnetic particles or the like having a diameter of several to several tens of millimeters from the upper opening of the carrying pipe in a dispersed manner so as to cause the magnetic particles or the like to magnetically adhere to the inner surface of the steel pipe near the circular mesh plate provided at the tip portion of the carrying pipe and adhere to each other to form a mass, thereby suppressing the outflow of petroleum or natural gas; and after the outflow of petroleum or natural gas has been suppressed, injecting the concrete or the like from the upper opening of the carrying pipe and curing the concrete.
 3. The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to claim 1, wherein the step of dropping the magnetic particles or the like in the elongated carrying pipe made of nonmagnetic material such as synthetic resin and suspended inside the steel pipe for petroleum or natural gas well that has been installed in the sea includes: hermetically sealing the upper opening of the carrying pipe with an feeding equipment for feeding magnetic particles or the like so as to suppress an internal flow in the carrying pipe and after the internal flow in the carrying pipe has been suppressed, dropping the magnetic particles or the like loaded into a feeding opening in the carrying pipe, whereby the magnetic particles or the like fall to a lower end of the carrying pipe without resistance, move along the flow of petroleum or the like in the steel pipe, reach a conical metal mesh attached to the carrying pipe, are blocked up by the conical metal mesh and magnetically adhere to the inner surface of the steel pipe, and a resulting adherent layer gradually grows downward so that the magnetic particles or the like reach the circular mesh plate provided at the tip portion of the carrying pipe, fill inside of the steel pipe and form a mass due to magnetic force, suppressing the outflow of petroleum or natural gas, and wherein after the outflow of petroleum or natural gas has been suppressed, a ball valve or the like provided at an upper portion of the carrying pipe is opened and the concrete or the like is injected and cured.
 4. The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to claim 1, wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes.
 5. The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to claim 2, wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes
 6. The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to claim 3, wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes 